August 3, 2013
12:45 PM (EDT)

News Release Number: STScI-2013-29

Hubble Finds 'Smoking Gun' After Gamma-Ray Blast

August 3, 2013: Ever since U.S. Air Force satellites serendipitously discovered gamma-ray
bursts in the 1960s, astronomers have been searching for the triggering
mechanism. Gamma-ray bursts are mysterious flashes of intense high-energy radiation that appear from random directions in space. These titanic explosions unleash as much energy in less than a second as the Sun does in 1 million years.

Now, astronomers are using NASA's Hubble Space Telescope to gather key
evidence on what powers short-duration gamma-ray bursts, which last
up to two seconds. Probing the location of a recent short-duration burst
in near-infrared light, Hubble found the fading fireball produced in the
aftermath of the blast. The afterglow reveals for the first time a new kind
of stellar blast called a kilonova, an explosion predicted to accompany a
short-duration gamma-ray burst. The kilonova is the "smoking gun"
evidence that short-duration bursts are sparked by the merger of two
small, super-dense stellar objects, such as a pair of neutron stars or a
neutron star and a black hole.